History of pack 1 change

In crates/flow/src/checkpoint.rs, lines 62–93 on c8917cf1f9310b5fbb0f6a44f016b6b956ab702b689992917cade6ceac375d65. Every change that wrote or deleted one of these lines, or deleted a line from between them. Exact, because each line keeps its identity across edits; edits elsewhere in the file are not here. Also: oxy log -L 62,93:crates/flow/src/checkpoint.rs.